Control device for the power units of aircraft



Jan. 23, 1951 R. z. HAGUE EI'AL CONTROL DEVICE FOR THE POWER UNITS OF AIRCRAFT Original Filed May 29, 1945 HOWARD A.ALEXANDER$ON ROBERT Z. HAGUE Patented Jan. 23 i951 oFFics CONTROL DEVICE FOR TEE POWER UNITS F AIRCRAFT corporation of Delaware Original application May 29, 1945, Serial No. 596,472. Divided and this application March 3, 1948, Serial No. 12,784

7 Claims.

The present application is a division of U. S. application Serial No. 596,472, filed May 29, 1945 by Howard A. Alexanderson and Robert Z. Hague and relates to improved control devices for the power units of aircraft.

An object of the invention is to provide a novel linkage arrangement for alternately effecting automatic or manual control.

Another object of the invention is to provide a novel linkage for effecting manual control upon failure of the operating medium for the automatic control.

Another object of the invention is to provide novel linkage means for effecting direct manual control upon failure of a normally operative automatic motor means.

Another object of the invention is to provide a novel linkage arrangement, including a walking beam operative in one sense for interconnecting a manually operated shaft and a second shaft to be controlled, and the walking beam operative in a second sense for permitting movement of said second shaft by an automatic motor means free of said first mentioned shaft, and a means for locking said walking beam from the latter operation upon failure of the operating medium for the motor means.

The above and other objects and features of the invention will appear more fully hereinafter from a consideration of the following description taken in connection with the accompanying drawing wherein one embodiment of the invention is illustrated by way of example.

The drawing is a diagrammatic view of the novel linkage arrangement for effecting manual control upon failure of the operating medium for automatic control.

Referring to the drawing, a control lever 3 is keyed to a main control shaft 4 which extends into a control unit indicated in the drawing by the letter A. The control lever 3 is connected by a link 2 to a suitable pilot's operative control lever, not shown.

A throttle valve 59 controls an air inlet conduit 58 of an aircraft engine. The'throttle valve 59 is controlled by a rod 60 operably connected as shown in the drawing to a throttle control arm Bl.

The throttle control arm BI is keyed to a shaft 62 rotatably mounted in a bearing formed in the casing of the control unit as indicated at 63. R0- tatably mounted in the shaft 82 is one end of the shaft 4. Y

There is provided a servo piston 64 for operating the throttle 59 through shaft 62. The pisat opposite sides of the piston 84.

The piston 64 has a piston rod 68 pivotally connected at one end to the piston 64 and at the opposite end pivotally connected to an operating arm 69 formed integral with the rod 62.

Keyed to the pilot's control shaft 4 is a second arm 10 connected through a link H to one end of a walking beam 12. The opposite end of the walking beam 12 is connected through a link l3 to the arm 69.

Pivotally connected at a point intermediate the opposite ends of the walking beam 12 is one end of a lever arm 14 which is aflixed at the opposite end to a shaft 15.

The shaft 15 is rotatably supported in bearing portions 16 and 11 formed apart of the control unit. Freely rotatable on the shaft 15 is an arm 18. The arm 18 is pivotally connected at the free end to a rod 19 which connects the arm 18 to a piston 88. The latter piston 88 is slidably mounted in a cylinder 8| into which opens at one end a passage 82 leading to a fluid pressure line such as oil under engine pressure. .The piston 88 is normally forced under pressure of the oil in an upward direction as viewed in the drawing.

A spring 83 is positioned between the piston and the upper end of the cylinder so as to force the piston in a downward direction upon oil pressure failure. whereupon the arm 18 is forced in a clockwise direction. An adjustable screw 84 projects through the arm 18 and is arranged so as to engage an abutment plate 85 on the arm 14 in the latter event so as to restrain movement of the arm 74 in a counter-clockwise direction. A stop pin 86 projects from aportion 81 of the casing of the unit so as to restrain the arm 14 from movement in an opposite direction.

The pilot's control lever may then efiect manual control of the throttle valve 59 through shaft 4, arm '8, link, walking beam 12, link 13, arm 69 and throttle control shaft 62.

The adjustable screw 84 is preferably adjusted so as to permit a small amount of angular travel of lever 14 between screw 84 and stop pin 86. During such manual operation of the throttle 59, lever arm 14 is driven between its restraining stops 84 and 86 rotating shaft 15.

At the opposite end of the shaft 15 there is affixed an arm 88 through which projects an adjustable screw 88. The screw 89 is arranged to engage a pin 88 which projects from an arm' 9'l, supported on shaft. The arm BI is freely rotatable on the shaft 15 and includes a second pin upward direction by spring I02.

92 which projects therefrom into a slot 93 formed in an arm 94 freely. rotatable on a pin 95 projecting from one 1end of a shaft 96. The shaft 96 is supported in a bearing 9'! formed apart of the casing of the control and the-shaft 96 may be rotatably' adjusted as described and claimed in the copendingdivisional application Serial No.

129,132 filed November 3, 1949 by Robert Z. Hague and' Howard A. Alexanderson and assigned to Bendix Aviation Corporation.

The arm 94 has an abutment plate 99 which bears upon one end of a plunger I slidably supported by'bracket portions IOI and biased in an Lever arm 94 is driven by pin 92 of arm 9| so as to move plunger I 00.

' The plunger I00 is arranged so as to operably contact at I02 one end of a valve stem I03 which is biased under force of a leaf spring I04 in an upward direction. A valve stem I03 has valve members I05 and I06 arranged so asto control passages 66 and 61 respectively opening into valve chamber I0! and leading to chamber 65 at opposite sides of piston 64 so as to control the movement of the piston 64. The fluid pressure line 82 opens intermediate the openings of passages 66 and 61 to valve chamber I01. A fluid medium outlet or drain passage I08 also opens from the valve chamber I01 at the upper and lower sides of valves I05 and I06 respectively.

Another valve chamber H0 is provided separated from the valve chamber I0'I by a sealing member III. Projecting through the sealing member III is a valve stem II2. At the lower end of the valve stem H2 is mounted a cylindrical valve I I3 having a spring II4 which tends to bias the valve H3 and stem 2 in an upward direction.

The fluid pressure passage 82 opens into the valve chamber 0 at the upper side of the valve II3 so that during normal operation the fluid pressure medium forces the valve II3 downward into the position shown in the drawing. The exhaust passage I08 has a port II5 opening into the housing of the control unit A and a port II6 opening into the chamber IIO but closed by the valve II3 when biased downward to the position shown in the drawing. A main drain passage Ill opens into the valve chamber H0. During normal operation the fluid medium is drained from the housing by suitable ports not shown.

When no pressure medium is available or upon oil pressure failure the drain valve II3 which is loaded by spring II4 is moved in an upward direction under force of the spring II4 serving two purposes. It causes the oil in the housing of the control unit A to drain to a predetermined low level by uncovering a drain port II6 so as to permit such drainage through port II5, passage I08, port II6, valve chamber H0 and through passage II! to the fluid outlet. Secondly the spring II4 urges valve stem II2 upward into contacting relation with the lower end of the valve stem I03 so as to actuate the valve stem I03 in an upward direction.

During such fluid pressure failure, movement of the pilot's control lever I so as to move arm 10 in a counter-clockwise direction causes movement in a counter-clockwise direction of the lever arm 14 between its restraining stops 86 and 84 whereupon valve stem II2 under force of spring Ii3 causes servovalve to move from its neutral position as shown in the drawing, to an upper position so as to uncover the ports leading to passages 66 and 61 so as to permit movement of the throttle 59 manually. Similarly upon movement of the lever arm 14 in a clockwise direction between its restraining stops 85 and 96 as upon manual movement of arm 10 in a clockwise direction lever arm 94 actuates through plunger I00 the valve stem I03 in a downward direction opening the ports to passages 66 and 61. It will be seen from the foregoing that the manual operation of the servovalve I03 not only permits the opening of the passage and 61 so that the manual operation of arm 69 and accordingly throttle 59 may be eiiected, but in the event slight pressure be available such movement of the valve I03 directs such slight pressure so as to effect piston 64' so as to assist the manual movement of the arm 69 and thereby assist in the manual control of throttle valve 59.

The latter feature of efiecting manual control of the position of the throttle upon pressure failure is described and claimed in the co-pending parent application Serial No. 596,472, filed May 29, 1945, by Howard A. Alexanderson and Robert Z. Hague and assigned to Bendix Aviation Corporation.

Automatic control of throttle When fluid pressure is available in excess of a predetermined valve, the piston is moved upward under the pressure medium from passage 82 against the force of spring 83. This latter action forces link 19 upward moving lever 18 in a counterclockwise direction so as to permit lever arm 14 to move free of the restraining screw 84. Likewise upon such fluid pressure medium becoming effective the valve H3 is moved downward against spring II4 permitting the servovalve I03 to move free of the valve stem II2 under automatic control.

In order to effect the latter automatic control there is provided a pressure responsive bellows assembly including an evacuated bellows I2I supported at one end by a stud I22 carried by a portion I23 of the control unit A.

A spring I24 is positioned within the evacuated bellows I2I tending to expand the same. At the opposite end of the bellows I2I there is provided a movable plate I25 interposed between the bellows I2I and a second bellows H6. The bellows I20 is mounted at the opposite end by a portion I21 of the control unit A.

A passage I29 formed in the control unit leads from the interior of the bellows I26 to a conduit which leads to the air intake manifold conduit of the engine not shown herein. Thus the bellows I26 is controlled by the intake manifold pressure of the engine which is in turn affected by the position of the throttle valve 59.

The movable plate I25 between the manifold pressure bellows I26 and evacuated bellows I2I is connected through a link I3I, leaf spring I32, beam I33 and the leaf spring I04 to the servovalve I03. Beam I33 in the schematic drawing contains at opposite ends the preloaded leaf springs I04 and I32 which permit deflection of the servovalve I03 by plunger I00 and valve stem II2 without excessively loading the belows assembly. The beam I33 may however be made in the form of a solid beam and link I3I provided with a preloading mechanism which maintains the link I3l at a fixed length.

The selected pressure or datum of the bellows assembly may be changed by moving a pin I34 on which beam I33 is pivotally supported. Pin

m is adjusted through operation of suitable mechanism, such as disclosed and claimed in the copending parent application Serial No. 596,472, filed May 29, 1945 by Howard A. Alexanderson and Robert Z. Hague and assigned to Bendix Aviation Corporation.

It will be readily seen however from the foregoing that upon an increase in the intake manifold pressure above the selected pressure there will result an expansion of the manifold pressure bellows I28 causing the beam I 33 to be shifted in a clockwise direction whereupon the servo-valve I03 will be adjusted upward causing a pressure. medium to be' applied through the passage 60 to the upper side of the piston 84 and exhausting the lower side through passage 81. This action will cause the piston 64 to be adjusted downward so as to adjust the arm 89 in a counter-clockwise direction moving valve 59 of the drawing through rod '0 in a valve closing direction decreasing the intake manifold pressure until the valve I0! is returned to a neutral. position. An opposite effect is of course produced upon the intake manifold pressure dropping below the selected value.

A conduit 282 leads from the piston chamber ll for providing a fluid medium for further controlling the induction pressure through operation of suitable mechanism, while-conduits "A and 82A also lead to mechanism affecting the latter control as described and claimed in the copending parent application Serial No. 596,472 filed May 29, 1945 by Howard A- Alexanderson and Robert Z. Hague and divisional application Serial NO. 111,896 filed August 22, 1949 by HOW- I In the event of a hydraulic pressure failure the I novel manually operable mechanical linkage 19, II, l2, l3 and I4 is arranged so as to provide direct manual throttle control as heretofore explained. This linkageis particularly effective at the time of starting the aircraft engine. The manual throttle travel is sufiicient to give normal power at take-off engine speed at sea level.

Although only one embodiment of the invention has been described and illustrated in detail, it is to be expressly understood that the same is not limited thereto. Various changes may be made in design and arrangement of the parts illustrated, as will be apparent to those skilled in the art. For a definition of the limits of the invention, reference should be had to the appended claims.

What is claimed is:

1. The combination comprising a first rotatable shaft. 9. second rotatableshaft, a walking beam operatively connecting said first and second rotatable shafts, stop means for limiting movement of said walking beam in a first sense and permitting movement of said walking beam in a second sense so as to drivingly connect said first and second rotatable shafts, and means for placing said stop means out of said limiting relation so as to permit movement of said walking beam in said second sense.

ing a spring biased servo piston for operating said stop means.

4. The combination defined by claim 1 including a hydraulic motor means for rotatably positioning' said first shaft, and a spring biased servo piston for operating said stop means to drivingly connect said motor means to said second shaft through said walking beam upon the hydraulic pressure of the operating medium for said motor means exceeding a predetermined value.

5. The combination comprising a first rotatable shaft, a second rotatable shaft concentrically mounted relative to said first shaft, a walking beam, first linkage means connecting one end of the walking beam to said first rotatable shaft, second linkage means connecting the opposite end of the walking beam to said second rotatable shaft, an arm pivotally supporting said walking beam at a point intermediate said opposite ends, said arms movable for permitting free movement of said first shaft relative to said second shaft, a second arm for locking said first mentioned arm from the latter movement while permitting pivotal movement of said walking beam relative to said first arm so as to drivingly connect said first rotatable shaft to said second rotatable shaft.

6. The combination defined by claim 5 including a hydraulic motor means for positionin said second rotatable shaft, a piston operatively connected to said second arm, a common hydraulic pressure source for operating said piston and motor means, said piston biased to a first position to cause said second arm to release said first mentioned arm upon the hydraulic operating pressure exceeding a predetermined value, and a spring for biasing said piston to a second position to cause said second arm to lock said first arm upon failure of the hydraulic operating pressure.

7. The combination comprising a first rotatable shaft, a second rotatable shaft, a walking beam,

first means connecting said walking beam to the first and second shafts, a motor operatively con-' 2. The combination defined by claim 1 in which I said motor, second means connecting said walking beam to said control means, said walking beam movable in a first sense for actuating said control means so as to effect movement of said second shaft by said motor, and said walking beam movable in a second sense for drivingly connecting said first. and second shafts, means for limiting movement of said walking beam in said first sense so as to effect movement of said walking beam in said second sense and thereby drivingly connect said first shaft to'said second shaft, and means for placing said limiting means out of operative relation so as to discontinue the driving relation between said first and second shafts.

ROBERT z. HAGUE. HOWARD A. ALEXANDERSON.

REFERENCES c'rran The following references are of record in the file of this patent:

UNITED STATES PATENTS Number- Name Date 1,625,583 Payne Apr. 1927 2,892,585 Anderson Jan. 8, 1946 Smith Nov. 25, 1947 

